 /*******************************************************************************
  * Copyright (c) 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.core.internal.resources.mapping;

 import java.util.*;
 import org.eclipse.core.resources.*;
 import org.eclipse.core.runtime.IPath;

 /**
  * A description of the changes found in a delta
  */
 public class ChangeDescription {

     private List addedRoots = new ArrayList();
     private List changedFiles = new ArrayList();
     private List closedProjects = new ArrayList();
     private List copiedRoots = new ArrayList();
     private List movedRoots = new ArrayList();
     private List removedRoots = new ArrayList();

     private IResource createSourceResource(IResourceDelta delta) {
         IPath sourcePath = delta.getMovedFromPath();
         IResource resource = delta.getResource();
         IWorkspaceRoot wsRoot = ResourcesPlugin.getWorkspace().getRoot();
         switch (resource.getType()) {
             case IResource.PROJECT :
                 return wsRoot.getProject(sourcePath.segment(0));
             case IResource.FOLDER :
                 return wsRoot.getFolder(sourcePath);
             case IResource.FILE :
                 return wsRoot.getFile(sourcePath);
         }
         return null;
     }

     private void ensureResourceCovered(IResource resource, List list) {
         IPath path = resource.getFullPath();
         for (Iterator iter = list.iterator(); iter.hasNext();) {
             IResource root = (IResource) iter.next();
             if (root.getFullPath().isPrefixOf(path)) {
                 return;
             }
         }
         list.add(resource);
     }

     public IResource[] getRootResources() {
         Set result = new HashSet();
         result.addAll(addedRoots);
         result.addAll(changedFiles);
         result.addAll(closedProjects);
         result.addAll(copiedRoots);
         result.addAll(movedRoots);
         result.addAll(removedRoots);
         return (IResource[]) result.toArray(new IResource[result.size()]);
     }

     private void handleAdded(IResourceDelta delta) {
         if ((delta.getFlags() & IResourceDelta.MOVED_FROM) != 0) {
             handleMove(delta);
         } else if ((delta.getFlags() & IResourceDelta.COPIED_FROM) != 0) {
             handleCopy(delta);
         } else {
             ensureResourceCovered(delta.getResource(), addedRoots);
         }
     }

     private void handleChange(IResourceDelta delta) {
         if ((delta.getFlags() & IResourceDelta.REPLACED) != 0) {
             // A replace was added in place of a removed resource
 handleAdded(delta);
         } else if (delta.getResource().getType() == IResource.FILE) {
             ensureResourceCovered(delta.getResource(), changedFiles);
         }
     }

     private void handleCopy(IResourceDelta delta) {
         if ((delta.getFlags() & IResourceDelta.COPIED_FROM) != 0) {
             IResource source = createSourceResource(delta);
             ensureResourceCovered(source, copiedRoots);
         }
     }

     private void handleMove(IResourceDelta delta) {
         if ((delta.getFlags() & IResourceDelta.MOVED_TO) != 0) {
             movedRoots.add(delta.getResource());
         } else if ((delta.getFlags() & IResourceDelta.MOVED_FROM) != 0) {
             IResource source = createSourceResource(delta);
             ensureResourceCovered(source, movedRoots);
         }
     }

     private void handleRemoved(IResourceDelta delta) {
         if ((delta.getFlags() & IResourceDelta.OPEN) != 0) {
             closedProjects.add(delta.getResource());
         } else if ((delta.getFlags() & IResourceDelta.MOVED_TO) != 0) {
             handleMove(delta);
         } else {
             ensureResourceCovered(delta.getResource(), removedRoots);
         }
     }

     /**
      * Record the change and return whether any child changes should be visited.
      * @param delta the change
      * @return whether any child changes should be visited
      */
     public boolean recordChange(IResourceDelta delta) {
         switch (delta.getKind()) {
             case IResourceDelta.ADDED :
                 handleAdded(delta);
                 return true; // Need to traverse children to look for moves or other changes under added roots
 case IResourceDelta.REMOVED :
                 handleRemoved(delta);
                 // No need to look for further changes under a remove (such as moves).
 // Changes will be discovered in corresponding destination delta
 return false;
             case IResourceDelta.CHANGED :
                 handleChange(delta);
                 return true;
         }
         return true;
     }

 }

